Huge Bias value

I have an STF-8300C. While using the camera recently, I noticed the background sky value was always around a pixel value of 18,000. This did not change with exposure time. I then tried some bias frames and the pixel value was the same! before I used to take dark frames and the value was in the 700-800 range. What's going on here? Images with a background of 18,000 are not really useable...

 

if your dark and bias frames are high adu in the dark with the shutter closed or the camera inside with the cap on you might want to reset the usb offset.
in ccdops click the edit tab then select preferences , another dialog box will pop up showing select the options you want for ccdops
check the rectangular box in the upper right hand corner of that dialog and select show advanced menu in the popped up window
select ok and close ,the advanced tab will appear to the right
open advanced menu and select usb offset.
with the camera in the dark run the app and write it to the eeprom.
your value should return to around ADU 1000

 

Thanks! That seems to have corrected the problem. The first time I tried to write the value to EEPROM it said "checksum error". I did some more tinkering and for some reason the camera thought it was an ST-7. I changed it to STF-8300C and then things worked. What bugs me is why this changed by itself. The camera worked fine not too long ago... I hope the EEPROM is not randomly changing things back to some other configuration. Thanks again for the assist.

 

My most sincere thanks go out to "kwalker50" for this information.

My new STF-8300M came from the factory with ADU's at 4000 when taking Dark and Bias frames.
I could not calibrate my light frames at all with camera in this condition.
This is my first SBIG camera, so I had no idea whatsoever on how to solve this problem.

I do not see any mention in the Operating Manual regarding the "USB Offset". Why? It seems to be a pretty important function.
And I think the adjustment should not be buried in a less conspicuous CCDops menu.
I also do not understand why my new camera, with fully current drivers and firmware, was delivered with this problem.

Thank you "kwalker50"! You saved this new STF-8300 owner a lot of frustration.

Doug

 

Adam,
Thank you for your reply. Your concern is duly noted, however I did perform the simple adjustments in CCDOpps and my STF-8300 accepted them and is performing very well.